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Meeting customer demands for order-based production and make-to-stock production policies against holding and non-holding costs are fundamental functions for businesses to ensure. For these policies, finite capacity buffers between machines is of great importance. WIP, production rate and profit values, the key performance indicators of the transfer line, affect the sustainable economics of companies. It is important to investigate how the production rate, one of the most important performance indicators, and its CPU time are affected by the reliability parameters of the machines, the convergence rate and the analytical methods applied. In this study, the theoretical computational convergence analysis of the Dallery-David-Xie (DDX) algorithm is conducted on balanced transfer lines consisting 20, 30 and 50-machines with four different reliability parameters, each having finite buffers. The results show that the performance of the DDX algorithm is very sensitive to the convergence rate. The CPU times spent based on the different convergence rates used in the applied DDX algorithm significantly differ from each other at a 95% confidence interval. Additionally, the study investigates uniformly, ascending order and descending order buffer distributions to maximize the profit value and minimize WIP in the transfer line. The initial buffer configuration affects the key performance indicators on balanced transfer lines with different reliability parameters. [ABSTRACT FROM AUTHOR]

We consider the Reconfigurable Transfer Line Balancing Problem. This problem consists of allocating a set of operations (necessary to machine a single part) to different workstations placed into a serial line. Each workstation can contain multiple machines operating in parallel. The machines considered are mono-spindle head CNC machines which may imply sequence-dependent setup times between operations in order to perform tool changes. Therefore, the operations allocated to a workstation should be sequenced. Besides, accessibility, inclusion, exclusion and precedence constraints between operations are considered. In this article, we propose a polynomial exact algorithm that balances the transfer line provided the overall sequence of the operations (called 'giant sequence') is given. We use this algorithm to solve the balancing problem when the overall sequence of operations is not fixed by embedding it in a metaheuristic framework. We perform experimentation on literature instances. The results obtained show the effectiveness of the proposed approach compared to literature. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Refinery Engineering is the property of Petroleum Refinery Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Understanding the transfer of embodied emissions along trade chains is crucial for promoting sustainable economic development. Here, we constructed the provincial inventory of emissions of 6 typical air/aquatic/solid pollutants (SO 2 , NO X , Dust, COD, NH 3 –N, and Solid wastes) via a multiple regional input-output (MRIO) model. We quantified the emissions responsibilities from both producer and consumer perspectives, adopting the 'Beneficiaries are responsible' principle for allocation. Further, we calculated appropriate payments or subsidies for each province's emissions using the slacks-based Data Envelope Analysis (SBM-DEA), aiming to provide a fair and transparent reference for China's current fiscal transfer payment system. Our findings revealed significant progress in emission reductions between 2012 and 2017 by 36.64%–66.49% excluding Solid wastes. Provinces within the Yangtze River Delta and Guangdong were the primary emitters at the consumption end, while provinces in Central, Western, and Northeastern China bore the brunt of embodied emissions through trade at the production end. In 2012, a dominant emission transfer was from developed to undeveloped provinces. However, by 2017, a new trend emerged, with emissions being transferred between provinces with similar levels of financial development. The secondary industry was the largest adsorber for the emission transfer, and reductions in emissions from this sector benefited the output of provinces who experienced rapid development during 2012–2017. Based on the offsetting calculated by this work, the current transfer payments system in China is not fair for some provinces who paid more or accepted less than they deserved. Some provinces should take a more active gesture in pursing their development instead of relying upon the transfer which they do not deserve. This study provides a comprehensive understanding of emissions from various perspectives, highlighting changes in inter-provincial and inter-industrial transfer pathways, which was valuable for multi-regional management efforts aimed at aligning national economic development with ecological conservation goals. [Display omitted] • The emission responsibility of air/aquatic/solid pollutant of 31 provinces is allocated in fairness. • Inter-provincial and inter-industrial transfer pathways are identified. • Emissions embodied in the transfers between provinces with similar levels of financial development become a new trend. [ABSTRACT FROM AUTHOR]

An analytical model for evaluating the throughput of two-machine lines, characterised by intermediate buffer with finite capacity, deterministic processing times and multiple failure modes for each machine is presented in this paper. Both operation-dependent failure and time-dependent failure are captured in a unique model as extension of the existing literature that was dealing with either one of them. Each machine has two failure modes, one is operation-dependent and the other is time-dependent. Time to failure and time to repair are assumed to be geometrically distributed. The presented method calculates the steady-state probabilities of the manufacturing system with a computational effort that depends only on the number of failure modes and not on the buffer capacity. A performance comparison of the proposed model with existing techniques is also reported, the aim is to show the error introduced by an analytical model that considers the operation-dependent failure mode as approximation of the time-dependent one. [ABSTRACT FROM PUBLISHER]

Copyright of Petroleum Refinery Engineering is the property of Petroleum Refinery Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Plasma driven particle accelerators represent the future of compact accelerating machines and Free Electron Lasers are going to benefit from these new technologies. One of the main issue of this new approach to FEL machines is the design of the transfer line needed to match of the electron-beam with the magnetic undulators. Despite the reduction of the chromaticity of plasma beams is one of the main goals, the target of this line is to be effective even in cases of beams with a considerable value of chromaticity. The method here explained is based on the code GIOTTO (Bacci et al., 2016) that works using a homemade genetic algorithm and that is capable of finding optimal matching line layouts directly using a full 3D tracking code. [ABSTRACT FROM AUTHOR]

A body shop in an automotive factory consists of many sub-lines which are highly automated transfer lines, and the sub-lines are merged in many assembly operations. To design a body shop, the layout concepts based on welding technologies and the material handling systems should be considered and optimized. Two types of layout concepts are widely used, and they are known as the layered build layout and the modular build layout. There are also two part transfer policies in a transfer line with unreliable machines and no buffer. The first transfer policy is the asynchronous transfer which allows a part to move to the next operation independently. The second policy is the synchronous transfer which allows parts to move to the next operation whenever all operations in a sub-line are completed. In this study, we compare two types of transfer policies in two different layouts having many transfer lines and assembly operations in automotive body shops by simulation study. [ABSTRACT FROM AUTHOR]

The 80 K liquid nitrogen distribution is one of the essential sub-systems of SST-1 cryogenics system. It consists of 80 K Thermal shields, current feeders system, integrated flow distribution and control system, pre-cooling heat exchanges and purifier of helium plant system. The maximum operating pressure of liquid nitrogen is 1.9 bar (a) from the source storage tanks. Preliminary, authors observed the frosting in one of the section of return LN, cryo line near the phase separator interface. Due to this problem, they were unable to collect the phase separated LN, in the sub-cooler back. Appropriate investigation of leaks, reason for the leaks identified. Welding protocols (ASME section IX) and replacement of Bellows (as per EJMA standards) were carried out under satisfying the flexibility criteria. The evacuation of transfer lines, insulation wrapping, welding and assembly in congested space and safety aspect as 12 m height were the challenges experienced during repairing task. Due to this activity, the huge amount of LN, fluid has been saved. In this paper, author will mainly focus on the identification of weld leaks, welding and repairing process, vacuum evacuation process, design of sealing set up, NDT testing of weld joints and helium leak testing at operating condition of cryogenic transfer lines after welding task. [ABSTRACT FROM AUTHOR]

This article deals with the analytical modeling of transfer lines consisting of two machines decoupled by one finite buffer. The innovative contribution of this work consists in representing a particular behavior that can be found in a number of industrial applications, such as in the ceramics and electronics industries. Specifically, the buffer significantly affects the line’s performance as, when it is accumulating or releasing material (i.e., when one machine is operational and the other machine is under repair), it forces the operational machine to slow down. Conversely, when both machines are operational they can work at a higher capacity since the buffer is bypassed. Thus, two levels for the machine capacity can be identified, based on the conditions of the machines and, consequently, the state of the buffer. The system is modeled as a discrete-time, discrete-state Markov process. The resulting two-Machine one-Buffer Model with Buffer Bypass is here called 2M-1B-BBmodel. The analytical solution of the model is obtained and mathematical expressions of the most important performance measures are provided. Finally, some numerical results are discussed. [ABSTRACT FROM AUTHOR]

The paper deals with analytical modeling of transfer lines consisting of two machines decoupled by one finite buffer. In particular, the case in which a control policy (referred as 'restart policy') aiming to reduce the blocking frequency of the first machine is addressed. Such a policy consists of forcing the first machine to remain idle (it cannot process parts) each time the buffer gets full until it empties again. This specific behavior can be found in a number of industrial production systems, especially when some machines are affected by outage costs when stops occur. The two-machine one-buffer line is here modeled as a discrete time Markov process and the two machines are characterized by the same operation time. The analytical solution of the model is obtained and mathematical expressions of the most important performance measures are provided. Some significant remarks about the effect of the proposed restart policy on the behavior of the system are also pointed out. [ABSTRACT FROM AUTHOR]

This article focuses on analytical models of two-machine one-buffer Markov lines including waste production. The aim is to compute the probability of producing good parts, referred to aseffective efficiency, when waste production is related to stoppages of the first machine. This problem is common in industrial fields where parts are generated by a continuous process; e.g., in high-speed beverage packaging lines. Two innovative models including waste production are presented: the WP-Basic Model extends the model of a basic two-machine–one-buffer transfer line; the WP-RP Model extends the model of a two-machine–one-buffer transfer line with a restart policy operating on the first machine (i.e., when the first machine is blocked because the buffer is filled, it is not allowed to resume production until the buffer becomes empty). The two existing models are improved by distinguishing, at any time step the first machine is operational, whether it is producing a good or a bad part. The probabilities of the system being in any feasible state are analytically derived for both the WP-Basic Model and the WP-RP Model. Then, the obtained probabilities are used to determine the performance measures of interest; i.e., waste probability and effective efficiency. Finally, some numerical results are provided to illustrate the effectiveness of the WP-Basic Model and the WP-RP Model. [ABSTRACT FROM AUTHOR]

A proper cryogenic environment is essential for the operation of superconducting devices. A test area for the superconducting radio-frequency modules (SRF) has been established in the RF laboratory at National Synchrotron Radiation Research Center in Taiwan; these modules require much liquid helium during conditioning and performance tests; a cooling capacity of 120 W is expected for the acceptance test of the SRF module. The cryogenic environment of the test area is completed on transferring the liquid helium over a remarkable length of 205 m from the two cryogenic plants at Taiwan Light Source, with a valve box located at each end to control and to measure the cryogenic flow. Flexible cryogenic transfer lines of concentric four-tube type are chosen for both the supply of liquid helium and the return of cold helium gas. Functional examination of this long transfer system was first achieved with a 500-L Dewar in the radio-frequency laboratory; an SRF module was then installed in the test area for practical operation. The primary concern about the cryogenic transfer system is the heat loss; a measurement technique based on the principle of thermodynamics is developed and proposed herein. With the available sensors inside the valve boxes and the heaters inside the 500-L Dewar and the test SRF module, this technique has proved promissing from the measured results. [ABSTRACT FROM AUTHOR]

Abstract: A transfer system for liquid nitrogen (LN2) installed at National Synchrotron Radiation Research Center (NSRRC) to provide LN2 required for the superconducting equipment and experimental stations has a LN2 transfer line of length 160m and pipeline of inner diameter 25mm, a phase separator (250 L) and an automatic filling station. The end uses include two cryogenic systems, one Superconducting Radio Frequency (SRF) cavity, five superconducting magnets, monochromators for the beam line and filling of mobile Dewars. The transfer line is segmented and connected with bayonet couplings. The aim of this work was to investigate, by numerical simulation, the effects on the heat load of the gap thickness of the bayonet assembly and the thickness of vacuum insulation. A numerical correlation was created that has become a basis to minimize the head load for future design of bayonet couplings. [Copyright &y& Elsevier]

The outline design of a fully superconducting motor for liquid hydrogen pump with a magnesium-diboride (MgB2) superconducting wire is carried out to present various advantages arising from its prospective performances. The squirrel-cage rotor winding composed of superconducting loops with the MgB2 wire enables us to operate the motor not only in a slip mode but also in a synchronous rotation mode, and consequently the rotor winding loss can be suppressed drastically. Furthermore, it would be expected that the stator winding loss becomes smaller by using the MgB2 wire compared with familiar normal metals as typified by a copper. The time evolution of magnetic field distribution around the stator winding is obtained by means of a finite element analysis in order to estimate the AC loss and the primary circuit resistance. [ABSTRACT FROM AUTHOR]

This paper describes an approximate analytical method for evaluating the average values of throughput and buffer levels of closed three-machine production systems with finite buffers. The method includes a new set of decomposition equations and a new building block model. The machines have deterministic processing times and geometrically distributed probabilities of failure and repair. The numerical results of the method are close to those from simulation. The method performs well because it takes into account the correlation among the numbers of parts in the buffers. Extensions to larger systems are discussed. [Supplementary materials are available for this article. Go to the publisher's online edition of IIE Transactions for the following free supplemental resource: Appendix of additional numerical results] [ABSTRACT FROM AUTHOR]

Abstract: CTF3 is the CLIC Test Facility at CERN to demonstrate the idea of high power RF generation by means of a drive electron beam. A train of bunches with 140ns pulse length will pass through the PETS (Power Exchange and Transfer Structure) area to generate the RF power. The current in train of bunches will be increased by combining bunches in the Delay Loop (DL) and Combiner Ring (CR). These bunches, extracted from the CR with bunch length of 8.3ps will be transported at 150MeV from the CR to CLEX area through a transfer line (TL-2). In this transfer line bunch length will be compressed further by tuning the R 56 parameter (longitudinal dispersion). Therefore, this line serves two purposes i.e. it transports bunches with proper optical matching as well as compresses them longitudinally. In this paper, we outline the optics design of the TL-2, which is able to tune the R 56 in a very wide tuning range i.e. from −0.30 to +0.30m. Being a test facility, such a wide tuning range of R 56 is required. Besides, a sextupole scheme optimization for suppression of second order term T 566 (second order longitudinal dispersion) is discussed. In entire range of tuning, no standard method, such as—I transformer can be used to reduce the geometrical aberrations, generated by T 566 correcting sextupoles. Therefore, another scheme of sextupoles is evolved, in which the geometrical aberrations are controlled by the initial Twiss parameter optimization. With this sextupole scheme we have very small dilution in the transverse emittance. [Copyright &y& Elsevier]

Abstract: A simple innovation is proposed in this work: to use interface (transfer line, TL), which allows quantitative mass transfer between two gas chromatographs. This approach assumes that one chromatograph serves as a conventional GC apparatus and the second one only as a thermostat with the appropriate detector(s) mounted. Two possible applications of the TL were tested: an “inlet–TL–detector” system and a system for dual-detection analysis, i.e. mass spectrometry and atomic emission detection. Results obtained for both of the systems show that the interface enables effective connection of two independent chromatographs. The transfer line is a manufacturer-independent innovation (with its own electronics), easy to set up and maintain. [Copyright &y& Elsevier]

We develop a model of a failure-prone, bufferless, paced, automatic transfer line in which material flows through a number of workstations in series, receiving continuous processing along each workstation. When a workstation fails, it stops operating, and so do all the other workstations upstream of it. The quality of the material trapped in the stopped workstations deteriorates with time. If this material remains immobilized beyond a certain critical time, its quality becomes unacceptable and it must be scrapped. We develop analytical expressions for important system performance measures for two cases. In the first case, the in-process material has no memory of the quality deterioration that it experienced during previous stoppages, whereas in the second case it has. In both cases, we assume that the workstation uptimes and downtimes follow memoryless distributions. We use the analytical expressions to numerically study the effect of system parameters on system performance. To evaluate the memoryless assumption, we compare the performance of the original model to that of a modified model in which the workstation downtimes do not follow memoryless distributions. The performance of the modified model is obtained via simulation. [ABSTRACT FROM AUTHOR]

The project ‘CERN neutrinos to Gran Sasso (CNGS)’, a collaboration between CERN and the INFN (Gran Sasso Laboratory) in Italy, will study neutrino oscillations in a long base-line experiment. High-energy protons will be extracted from the CERN SPS accelerator, transported through a 727 m long transfer line and focused onto a graphite target to produce a beam of pions and kaons and subsequently neutrinos. The transfer line requires a total of 78 dipole magnets. They were produced in the framework of an in-kind contribution of Germany via DESY to the CNGS project. The normal conducting dipoles, built from laminated steel cores and copper coils, have a core length of 6.3 m, a 37 mm gap height and a nominal field range of 1.38 T–1.91 T at a maximum current of 4950 A. The magnet design was a collaboration between CERN and BINP. The half-core production was subcontracted to EFREMOV Institute; the coil fabrication, magnet assembly and the field measurements were concluded at BINP in June 2004. The main design issues and results of the acceptance tests, including mechanical, electrical and magnetic field measurements, are discussed. [ABSTRACT FROM AUTHOR]

The Levitated Dipole Experiment ILDX) is an innovative facility to study plasma confinement in a dipole magnetic field, created by a superconducting solenoid (floating coil), which is magnetically levitated in the center of a 5 m diameter by 3 m tall vacuum chamber. This persistent mode, floating coil F-coil) consists of a Nb3Sn magnet installed inside a high-pressure vessel filled with 12.5 MPa helium gas at room temperature. It is surrounded by a high heat capacity fiberglass-lead composite radiation shield and by a toroidal vacuum shell. The built-in tube heat exchanger serves to cool the magnet, the helium vessel, and the thermal shield. When positioned at the lower part of the vacuum chamber the F-coil is cooled by retractable cryogenic transfer lines to about 4.5 K and it is charged inductively by the charging coil installed outside of the vacuum chamber. Then the helium flow is interrupted, the heat exchanger is pumped out, retractable lines are disengaged from F-coil ports, the ports are plugged, and the F-coil is lifted to the middle of the chamber to initiate and study plasmas. After several hours and just before the F-coil warms up to about 10 K it is lowered down for the next re-cooling or for discharging. This paper describes the F-coil cooling system and inductive charging system operation and performance. [ABSTRACT FROM AUTHOR]

Economic efficiency of a multi-station transfer line (TL) is evaluated directly by the quantity of parts produced; therefore, each single manufactured part counts. The contribution presents an approach which applies a reliability-adaptive operating strategy in combination with tool derating. It is the objective to hold the system harmonisation of tool changes as maintenance actions. The significant effectiveness of the approach is demonstrated by different configurations and contexts. The output-time function of a TL without reliability-adaptive control is compared with functions of a system with reliability-adaptive control. [ABSTRACT FROM AUTHOR]

This paper reports the effect of transfer line (TL) internal diameter (i.d.) on gas chromatographic separation characteristics such as efficiency and speed, when a multicapillary (MC) column is used for speciation analysis of mercury. Five different TL consisting of fused-silica capillaries with 0.15, 0.20, 0.25, 0.32, and 0.53 mm i.d. are compared. The separation efficiency and total chromatographic run time are critically affected by the i.d. of the TL. Narrow capillaries (i.d.≤0.20 mm) produce minimum peak dispersion whereas wide capillaries result in narrow peaks and shorter chromatographic analysis times. A thermodynamic approach is proposed to describe the motion of the analytes through the separation column and TL. The model provides good agreement with the experimental data for high pressures (≥35 psig) and wide TL (≥0.25 mm i.d.). [ABSTRACT FROM AUTHOR]

An outlet transfer line tube of an ethylene-cracking furnace failed after five years of service. The tube, made from Incoloy alloy 800H, developed cracks that penetrated the entire thickness. Optical and scanning electron microscopy, X-ray diffraction, and microhardness tests were used to evaluate the failed tube. It was found that the tube was considerably embrittled by high-temperature carburization, leading to intergranular fracture at the inner surface. Carburization appeared to have been caused by high-temperature exposure to the carbonrich atmosphere associated with the coke adhered to the inner surface. Additionally, the decrease in heat transfer due to the coke deposits caused the wall temperature to increase during service. However, at the outer surface, the tube fractured by a fatigue process that could result from the use of a counterweight to prevent sagging of the tube as a result of the coke deposition. Based on the results obtained, a short-term solution was to modify various process parameters to reduce the extent of coke deposition and/or increase the frequency of decoking and to discontinue the use of a counterweight. However, the long-term solution is to replace alloy 800H. [ABSTRACT FROM AUTHOR]

The successful application of high temperature superconducting power cables requires improved flexible cryostats with respect to their thermal heat load between environment (300 K) and LN2 (77 K) operating temperature. Heat transfer through the thermal insulation consists of thermal radiation, solid and residual gas conduction. Considering this heat load contributions, a new concept for the thermal insulation arrangement is presented in this paper. The main advantage of this concept consists in a separation of the thermal insulation and the supporting structure. This separation protects the thermal insulation from degradation by mechanical load. The fraction of solid heat conduction through this support structure is minimised by small contact areas and high heat conduction lengths. Heat transfer due to residual gas conduction is reduced by improved evacuation conditions close to the cold wall. Finally the structure allows subdivision of the multilayer insulation ensuring an optimal number of layers with respect to their insulation thickness, i.e. an optimal layer density. [Copyright &y& Elsevier]

Copyright of OR Spectrum is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)